148 PTEKOrODA. 



Genus ATLANTA. 



Testa nautiliformis carinata semicartilaginosa, spira plan- 

 orbula. — Partly cartilaginous and formed like a little 

 Nautilus. 



45. Peronii, f. 63, 64, Lesueur. — Compressa, tenuis- 

 sime byalina ; anfractibus tribus medio apparentibus, ad 

 dorsum anguste et tenuiter carinatis ; apertura subtrigona. 

 — The broad and rather flat whorls, to the number of three, 

 are visible in the centre, and have on the dorsal side a thin 

 and narrow horny keel. 



46. Kekaudreni, f. 61, 62, Rang. — Subventricosa, tenuis 

 hyalina ; anfractibus duobus medio apparentibus ; carina 

 dor sale latissima ; apertura subquadrata. — The whorls, only 

 two of which are visible in the small umbilicus, are narrower 

 and more tumid than in sp. 47, and the keel is much 

 broader. The aperture is more squarely oblong. 



47. INELATA, f. 65, Ecmg.^Subcompressa, alba laevis; 

 anfractibus apicalibus celatis, ultimo umbilicato, carina 

 dorsali angusta ; apertura arcuata, labio acute et longe 

 producto. — The apical whorls are invisible, the central 

 umbilicus being small, and the outer edge of the aperture 

 is arched ii^ito a tongue-shaped process. 



